Re: installing discipline in the senders of email, that is a wholly different matter...
This is what I have done. At least while at work. I check emails a couple of times each day. While it doesn't seem to happen much now, with nearly every user working remotely, we used to have a lot of all staff emails, and in some cases, those who responded would reply all. This meant about 90% of the emails I got were noise to me. That's a lot of noise when you get 200 emails a day. Thankfully, since we started using Yammer, that chat has moved, and I rarely (if ever) check Yammer..